MESOSCALE PRECIPITATION DISCUSSION 0514
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
456 PM EDT SUN JUL 22 2018

AREAS AFFECTED...WESTERN NC...EXT SOUTHWEST VA

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 222056Z - 230030Z

SUMMARY...SLOW MOVING CELLS W/BACKBUILDING NEAR SFC TRIPLE POINT
POSE LOCAL FLASH FLOODING RISK THIS EVENING.

DISCUSSION...20Z SFC ANALYSIS DEPICTS THE TRIPLE POINT VERY NEAR
KHKY CONNECTING TO A STATIONARY OR SLIGHTLY SAGGING WARM FRONT
RETROGRADING IN RESPONSE TO SHORTWAVE ENERGY CROSSING THE
CUMBERLAND PLATEAU AND DEEPENING THE SURFACE WAVE.  AN OCCLUSION
EXTENDS NORTHWARD TO THE MAIN CENTER OF THE SYNOPTIC UPPER LOW IN
NE KY.  IN RESPONSE TO PRESSURE FALLS, THE BACKING FLOW HAS BEGUN
TO ADVECT DEEPER MORE UNSTABLE AIR WESTWARD WITH TEMPS IN THE
MID-80S AND TDS NEARING THE MID TO UPPER 60S ALLOWING FOR MLCAPES
TO NEAR 1250-1500 J/KG.  STRONG MOISTURE CONVERGENCE ALONG THE
FRONTAL BOUNDARY WITH THE ISALLOBARIC RESPONSE HAS DEVELOPED
CONVECTION NEAR GSO THAT ALSO IS BACKBUILDING WESTWARD SLOWLY. 
GIVEN THE COL IN THE MID-LEVEL FLOW WITH THE SHORTWAVE SLIPPING
SSE OUT OF THE CUMBERLAND PLATEAU...CELL MOTIONS HAVE BECOME
NEARLY STATIONARY OR SLIGHTLY CONVERGENT TO THE ISALLOBARIC
RESPONSE ALLOWING FOR CONCENTRATED RAINFALL TOTALS AND POSING THE
LOCAL FLASH FLOODING RISK...THOUGH WOULD SHIFT NORTHWARD SLOWLY IF
AT ALL.  GIVEN THE DEPTH OF MOISTURE, INSTABILITY...RAIN RATES OF
1.5-2"/HR ARE LIKELY POSING 2-4" TOTALS ESPECIALLY AT THE TRIPLE
POINT OR INTERSECTION WITH THE WARM FRONT AND INTO THE TROWAL INTO
SW VA. 

GALLINA

ATTN...WFO...GSP...RAH...RNK...

ATTN...RFC...LMRFC...OHRFC...SERFC...

LAT...LON   37018118 36928004 36477983 35818012 35258076
            35138129 35428205 36158180 36458161